Vacuum thermal annealer

ABSTRACT

A vacuum thermal annealing device is provided having temperature control for use with various materials, such as semiconductor substrates. A vacuum is used to remove air and outgas residual materials. Heated gas is injected planar to a substrate as pressure is quickly raised.  
     Concurrent with the heated gas flow, a chamber wall heater is turned on and maintains a temperature for a proper annealing time. Upon completion of the annealing process, the chamber wall heater shuts down and air is forced around the chamber wall heater. Additionally, cool gas replaces the heated gas to cool the substrate.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims benefit of U.S. Provisional ApplicationNo. 60/364,497, filed Mar. 15, 2002, which is hereby incorporated byreference in its entirety.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates generally to furnaces, and moreparticularly to a vacuum thermal furnace used in a manufacturing processto anneal semiconductor devices.

[0004] 2. Description of Related Art

[0005] Semiconductor device manufacturing has evolved into a delicateand sophisticated process requiring state of the art processingequipment, sophisticated clean room facilities and precise and accuratemetrology equipment. Semiconductor devices are typically manufactured bysuccessively depositing and patterning layer after layer of ultra-purematerials on a substrate. These layered materials are often as pure asone part per million and are often deposited with thicknesses as preciseas a few Angstroms. The deposition process is usually performedaccording to by some well understood process such as physical vapordeposition (PVD), chemical vapor deposition (CVD), ion beam deposition(IBD), plating, etc. Semiconductor devices are built up by depositingthese thin films onto substrates made of an elemental semiconductor(e.g., silicon or germanium) or compound (e.g., gallium-arsenide orindium-phosphide) semiconductor, patterning the films usingphotolithography and etching processes, and then repeating the sameprocesses using different materials and patterns. In addition to thinfilm deposition and photolithography processes, there are otherprocessing steps such as annealing, burning-in, and electrical testing,which are required to make semiconductor devices.

[0006] Modern processing techniques in most of these areas have beendeveloped to manufacture semiconductor devices with dimensions so smallthat an instrument, such as an atomic force microscope, is required toobserve the different details of millions of devices on the substrate.The degree of difficulty in manufacturing semiconductor devices hassignificantly increased over the years because of both thisminiaturization and increased complexity of semiconductor devices.

[0007] For example, in modern manufacturing environments, allowablelevels of contaminating particulates in process equipment and cleanrooms are often less than one particle per cubic foot, compared toseveral hundred particles per cubic foot a few years ago. Process gaspurity of five-nines (i.e., 99.999%) or better is now required to runmost processes, as compared with three-nines (i.e., 99.9%) purity in thepast. Further, thin film thicknesses are often controlled to within afew Angstroms across the entire substrate, as opposed to a fewnanometers. Additionally, processing windows have become extremelynarrow, requiring C_(pk) values (statistical process capability indices)of four sigma or better. In order to achieve these stringentmanufacturing requirements, semiconductor-processing equipment hasbecome more sophisticated. One process area, which has been forced toadapt to these new high levels of performance, is the annealing process.Requirements on temperature control and uniformity across the substrate,reduction in particulates on the substrate, reduction in gascontamination, and improved cleanliness has imposed more stringentrequirements for furnace performance and design.

[0008] Annealing processes have a direct affect on the texture of acopper or other metal-film layer such as tantalum or molybdenum. Thesize and orientation of the grain of the layer are controlled by theannealing process, and are critical to the electrical performance of themetal-film layer. This is especially so in microcircuits with very smallline-widths that include deep and narrow trenches.

[0009] In addition, advancements in the development of copperinterconnects has brought about the inclusion of other metals such asbismuth and magnesium as composites within the copper thin film. Thisrequires additional thermal annealing treatments or alloying forhomogenizing the composites, electrically activating the composites, andto provide contacts to other layers within the microcircuit.

[0010] Annealing processes are typically performed by furnaces such as aRapid Thermal Processor (RTP) 100 displayed in FIG. 1. Typically, theRTP 100 includes a process chamber 110, a substrate stage 120, a heatinglamp assembly 130, a process chamber door 140 and a motor shaft assembly150. The RTP 100 radiantly heats wafers or other substrates in a vacuumenvironment. Once a substrate is loaded into the RTP 100 process chamber110, the process chamber 110 is evacuated with a vacuum pump (not shown)and the heating lamp assembly 130 is powered on. Disadvantageously,substrates heat up very quickly and temperature is difficult to control,especially at lower temperatures. Furthermore, temperature uniformityacross a substrate is difficult to control because different lampsradiate with different intensities. In fact, non-uniform heating becomesa larger problem as lamps degrade and intensity differences betweenlamps increase. If a lamp burns out, the heating uniformity across thesubstrate becomes unacceptable for proper processing to occur.

[0011] In addition to non-uniform heating problems, conventionalfurnaces have proven to be inadequate for annealing newer materials usedin semiconductor devices such as copper, titanium, and tantalum.Although new techniques for thin film deposition have been developedwhich make, for example, copper thin film deposition feasible, there hasbeen little advancement in other processes, such as the annealingprocess. As a result, the transition from aluminum conductors to copperconductors has been very slow.

[0012] Since copper is more difficult to process than aluminum, thereare many problems that must be overcome before copper conductorscompletely replace aluminum conductors. Some of the problems associatedwith using copper include difficulty in producing fine copper patternsfound in integrated circuits, difficulty in polishing and planarizing acopper coated substrate, copper migration, and copper contamination.Annealing conditions directly contribute to all of these problemsbecause copper is extremely sensitive to high temperatures, and as aresult, needs to be annealed at a relatively low temperature (100° C. to400° C.). These low temperature annealing conditions make the RTP 100 aswell as other semiconductor furnaces unsuitable for processing advancedmaterials.

[0013] Although the RTP 100 or diffusion furnaces have conventionallybeen used to anneal copper, these furnaces are incapable of properlyannealing the copper at a controlled low temperature. One disadvantageof conventional diffusion furnaces is that temperatures ramp up and downslowly, thus requiring an extended period of time for the annealingprocess. Another disadvantage of conventional diffusion furnaces isnon-uniform heating of substrates from a substrate center to an outeredge (this non-uniform heating is referred to as “RTD” or Radial ThermalDelta). This non-uniform heating causes the copper on the outer edge ofthe substrate to anneal more quickly than the center (assuming a highertemperature on the edges relative to the center), creating pooruniformity across the substrate.

[0014] Although the RTP 100 heats rapidly, unlike the diffusion furnace,the RTP 100 also has disadvantages. The RTP 100 heats substrates rapidlyto elevated temperatures by activating heat lamps, which have a tendencyto heat very rapidly. These heat lamps are ineffective at lowtemperatures. Further, the RTP 100 lacks the capability of temperaturecontrol, which is required for proper copper annealing.

[0015] Hotplates may also be used for quick annealing associated withthe chemical mechanical planarization (CMP) process used in copperelectroplating. This type of annealing system fits into the mechanicalschemes of the electroplating systems. A substrate is set on thehotplate where it is annealed. Certain hotplate systems isolate thesubstrate from the plate with a blanket of inert gas. Hotplates,however, can produce “hot spots” on the substrate, which can produce anon-uniform anneal that can cause hillock peaks that make theplanarization process less effective.

[0016] Accordingly, there is a need for a vacuum thermal annealer. Thereis a more specific need for a thermal annealer with proper temperaturecontrol for use with high conductivity materials such as copper.

SUMMARY OF THE INVENTION

[0017] The present system and method provides a vacuum thermal annealingdevice for use with various materials. The device includes a processchamber for holding wafers or other substrates to be annealed, a heatingsystem, a pumping system, a gas distribution system, and a controlstation. Initially, wafers or other substrates are loaded into theprocess chamber of the annealing device. The process chamber is thensealed. Subsequently, a vacuum is drawn on the process chamber to removeair and outgas residual materials. Next, heated gas, which may be inert,forming gas, or hydrogen is injected by special injectors such that thegas flows planar to the surface of the substrate. The heated gas isprovided to the process chamber by the gas distribution system. Theheated gas quickly applies heat uniformly across the substrate. Thepressure in the process chamber is then quickly raised, preferably toapproximately 69 kPa (about 10 psia). An exhaust pressure controllermaintains the pressure in the chamber. Concurrent with the heated gasflow, at least one heater mantle turns on. Once the heater mantlereaches a desired stable temperature, the heated gas flow is reduced andheat from the heater mantle maintains a temperature for the properannealing time. A wafer or substrate mantle may also be employed in sucha way that adjacent substrate mantles are capable of concurrentlyheating both sides of the substrate located between the adjacentsubstrate mantles.

[0018] Once the annealing process is completed, the heater mantle shutsdown. Simultaneously, inert gas, forming gas, or hydrogen gas is forcedaround the heater mantle and exhausted out of the process chamber. Atleast one injected inert gas or reducing gas cool both the chamberheater mantle and the substrates quickly. The heated gas is also shutoff and cooled gas immediately flows through the special injectors tocool the substrates. The cooled gas, as with the heated gas, flowsplanar to the substrate for effective sweeping of the substrate. Whenthe substrate temperature is lowered to an appropriate level, theprocess chamber may be opened, and the substrates removed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019]FIG. 1 is a prior art diagram showing a rapid thermal processorfurnace;

[0020]FIG. 2 is a block diagram of components of an exemplary vacuumthermal annealing furnace, according to the present invention;

[0021]FIG. 3 is a diagram illustrating an embodiment of the vacuumthermal annealing system in a standby position ready to be loaded;

[0022]FIG. 4 is a diagram of components of an exemplary vacuum thermalannealing system in a processing position, according to the presentinvention;

[0023]FIG. 5 is a diagram of a top view cut-away of the vacuum thermalannealing system chamber;

[0024]FIG. 6 is a diagram illustrating the details of the mantle andinjector components of the vacuum thermal annealing system;

[0025]FIG. 7 is a diagram illustrating the door interlock of the vacuumthermal annealing system;

[0026]FIG. 8 is a diagram illustrating a pumping system and a gasdelivery system of the vacuum thermal annealing furnace of FIG. 3;

[0027]FIG. 9 is a diagram illustrating details of a heating unit;

[0028]FIG. 10 is a flowchart of a procedure for loading and processingof a substrate;

[0029]FIG. 11A is a flowchart showing steps for temperature controlduring the heating cycle in step 1011 in FIG. 10;

[0030]FIG. 11B is a flowchart showing steps for temperature controlduring the heating cycle in step 1011 in FIG. 10, which uses a cold andhot gas mixing technique;

[0031]FIG. 12 a diagram illustrating an alternative embodiment of thevacuum thermal annealing furnace having single substrate processingcapabilities; and

[0032]FIG. 13 is a diagram illustrating a plurality of vacuum thermalannealers of FIG. 9 coupled together.

DETAILED DESCRIPTION OF THE INVENTION

[0033]FIG. 2 is a block diagram showing components of an exemplaryvacuum thermal annealing furnace 200. The vacuum thermal annealingfurnace 200 includes a process chamber 210, a substrate holder 215, aheater system 220, an optional robot 225, a pumping system 230, a gasdistribution system 235, a control system 240, and a bus 260 whichcouples all of these components together. The control system 240 ishardware and/or software-based, which is coupled to some or all theother components in the vacuum thermal annealer 200. The substrateholder 215 (also referred to as a substrate mantle) is used to holdwafers or other substrates during an annealing process, and isconstructed from materials with favorable heat transfer properties, suchas aluminum or zirconia. Additionally, the substrate holder 215 can beinterchanged with a substrate holder made of different materials inorder to satisfy needs of a particular annealing application.

[0034] The control system 240 provides a central point from where othercomponents can be configured and controlled. For example, the controlsystem 240 allows a user to write recipes that include differentprocessing conditions. Software of the control system 240 will thencarry out the steps of the recipe. A typical recipe may includetemperature ramp-up rate, temperature set-point, dwell time, ramp-downrate, and gas type for activation at each step. The control system 240typically consists of a computing device with a graphical user interface(GUI), specially written software coupled to other more specializedhardware, and software such as dedicated temperature controllers.Temperature control algorithms, such as Proportional-Integral-Derivative(PID) algorithms, are included in the control system 240, and are usedto set and control a process temperature.

[0035]FIG. 3 is a diagram showing components of an exemplary vacuumthermal annealing system 300 in a standby mode (i.e., ready-to-be-loadedposition). The vacuum thermal annealing system 300 includes a processchamber 301, a chamber liner 303, a heater system 305, a substrateholder 307, an electrical feed-through 309, an injector system 311, avacuum connecting port 313, a chamber door 315, a chamber door liner317, a chamber door actuator 319, and an optional robot 321. The vacuumconnecting port 313 is a conventional pumping port used to pump gasesand vapors out of the process chamber 301. A gas distribution manifold(to be discussed in detail in connection with FIG. 4) is a piping systemdesigned to deliver gas uniformly to one or more substrates 327.Preferably, a programmable exhaust valve 325 is used to control anexhaust pressure within the process chamber 301.

[0036] As shown, the chamber door 315 is lowered from the processchamber 301 to allow the optional robot 321 to load one or moresubstrates 327 onto the substrate holder 307. The one or more substrates327 are then moved into a concentric position on one or more of thesubstrate holders 307. In the present embodiment, the one or moresubstrates 327 are first loaded onto the substrate holder 307 by theoptional robot 321. Alternatively, since the optional robot 321 is notrequired, an operator can manually load the one or more substrates 327.Although the optional robot 321 is not essential, the optional robot 321is preferable because robot handling of substrates reduces handlingdamage, reduces contamination, and improves consistency—resulting inbetter yields and better process control.

[0037] Once the one or more substrates 327 are loaded, the chamber door315 is then raised by the chamber door actuator 319, and placed intoposition to seal the process chamber 301 with one or more o-rings 323creating a vacuum seal. The chamber door actuator 319, which moves thechamber door 315 into a proper opened or closed position, may include atorque control device. This torque control device is used to force thechamber door 315 closed when a pressure in the process chamber 301 iselevated above atmospheric pressure. A positive door closure assures thechamber door 315 does not open when hazardous gases are used within theprocess chamber 301. The set of o-rings 323 between the process chamber301 and the chamber door 315 form a vacuum seal allowing the processchamber 301 to be pumped down to low pressures as will be described inmore detail in connection with FIG. 4. The set of o-rings 323 can bemade of materials, such as high temperature sealing elastomer, dependingon the particular application of the vacuum thermal annealing furnace300.

[0038] The heater system 305 is an electrical heating system whichtypically works by resistive or inductive heating, and is used primarilyto heat the substrate below the heater system 305, and secondarily toheat the process chamber walls and mantles. The incoming gas issuperheated as will be discussed in conjunction with FIG. 8.

[0039]FIG. 4. is an exemplary block diagram of the vacuum thermalannealing system 300 illustrating a process chamber 301 interfaced to agas distribution system 403 and a vacuum pumping system 411. In theembodiment of FIG. 4, the vacuum thermal annealing system 300 is in aprocess mode (i.e., where the substrates are ready to be annealed).

[0040] The vacuum thermal annealing system 300 is typically interfacedto a controller (not shown). The process chamber 301 may be a metalchamber, which is typically constructed out of stainless steel oraluminum. The process chamber 301 further includes doors, ports, wirefeed-throughs, plumbing connections as well as other equipmentconnections and vacuum seals (not shown). An interior of the processchamber 301 can also be lined with the liner 303 usually made out of ametal or ceramic such as zirconia.

[0041] The set of o-rings 323 between the chamber 301 and the chamberdoor 315 form a vacuum seal allowing the process chamber 301 to bepumped down to low pressures with the pumping system 411. When thepumping system 411 is turned on, air, moisture, and outgassed residualmaterials in the process chamber 301 are evacuated through the vacuumconnection port 313, which is used to attach the process chamber 301 tothe pumping system 411. The vacuum connecting port 313 is typically madeout of stainless steel, but can be made of other materials includingaluminum. Further, the vacuum connecting port 313 between the processchamber 301 and the pumping system 411 is usually accomplished through astandard vacuum connection such as an ISO K-100 or KF-40 as defined instandard vacuum books.

[0042] The pumping system 411 typically includes a set of, pumps andpressure gauges. The set of pumps usually comprises one or moremechanical pumps, dry-vacuum pumps, turbo-molecular pumps, or cryogenicpumps depending on a base pressure desired and type of process gas beingused. Similarly, the set of pressure gauges usually includes one or moreconvection gauges, capacitance manometers, or ion gauges, depending onthe pressure being measured. Finally, the gas distribution system 403 isa piping system, which delivers gas into the process chamber 301 in amanner that uniformly and rapidly heats substrates loaded in thesubstrate holder 307, and further rapidly cools the process chamber 301after the annealing process.

[0043]FIG. 5 shows a top view of the process chamber 301 and theconcentricity of various components contained therein. A substrateinjector system 501 is shown in relationship to the substrate 327. Theprocess chamber 301 with the chamber liner 303 is shown in a cut-awayview. The substrate holder 307 is shown with the substrate 327 in theprocessing position. The chamber door 315 and the chamber door liner 317are shown in a cut-away view representing a relationship of thesubstrate 327 to the chamber door 315 in a closed position.

[0044]FIG. 6 is a cut-away, exploded view of the substrate holder 307and the heater system 305. A large substrate 601 (e.g., a 300 mmdiameter wafer) is shown resting in position on associated largesubstrate pedestals 603, which may be, for example, 9 mm high. A smallersubstrate 605 (e.g., a 200 mm diameter wafer) is shown resting onassociated small substrate pedestals 607, which may be, for example, 6mm high. FIG. 6, illustrates that the substrate holder 307 is able toaccommodate two substrate diameters or sizes. Typically, two substratesizes will not be loaded simultaneously. Provisions may be a made tohold additional substrate sizes in similar ways with additionalpedestals.

[0045]FIG. 6 further shows that a part of the injector system 311 risesabove the large substrate 601 such that gas flow from orifices in theinjector system 311 will flow planar to and across the top surface ofthe large substrate 601. Additionally, FIG. 6 illustrates that theinjector system 311 rises above the large substrate 601 such that itwill shield or deflect heated gases that are rising in a heat plume fromwithin the process chamber 301. Shielding of the large substrate 601 bythe injector system 311 portion isolates any substrate from the heatplume.

[0046] The substrate holder 307 includes a plurality of small substratepedestals 607 and large substrate pedestals 603 that are used to supportthe small and large substrates 605, 601 during the annealing process,and separate substrates from a surface of the substrate holder 307.There may be additional or other pedestals of different heights inrelationship to a surface of the substrate holder 307, and positionedsuch that more than one substrate diameter may be processed within thevacuum thermal annealing system 300. The small and large substratepedestals 607, 603 are typically constructed of the same material as thesubstrate holder 307 and are rounded at a contact point with thesubstrate 605, 601 to minimize substrate contact. The design of thesmall and large substrate pedestals 607, 603 minimize thermalconductance between the substrate 605, 601 and the substrate holder 307and allows sweeping gases to flow under and around all surfaces of thesubstrate 605, 601.

[0047] Any substrates 327, 605, 601 that are loaded into the processchamber 301 are heated by the heater system 305 and by a superheated gassupplied by a gas heater, which will be discussed in more detail withreference with FIG. 9. The heater system 305 heats the substrate 605,601 to a preset value as is further discussed with reference to FIG. 8below. Similarly, the gas heating system of FIG. 9 heats incoming gas toa desired value so that gas enters the process chamber 301 preheated asis further discussed with reference to FIG. 8 below. The heated gas maybe injected with the special injector system 311 such that the gas flowsplanar to and around the surface of the substrate 605, 601. A pluralityof orifices 609 in the injector system 311 are directed toward thesubstrate 605, 601. The orifices 609 are typically sized such that thereis an aspect ratio of between 4:1 and 10:1 as compared with a distancebetween an injector wall and the substrate 605, 601 and the diameter ofthe orifice 609. The orifices 609 are typically bored with a laser,which produces a smooth wall on the orifice 609. The smooth wallmaintains proper gas flow characteristics such that, at a given deliverypressure, each orifice 609 will flow a similar amount of gas. Typically,an inert gas, a forming gas, and/or a hydrogen gas are used, forexample, because these gases are allowed to flow directly over anysemiconductor device to remove oxidizers and to act as reducing agentsthat affect the desired properties of the semiconductor device.

[0048]FIG. 7 illustrates an exemplary cut-away view of the processchamber 301, showing a chamber door 315 and o-rings 323. Between the setof o-rings 323 is a groove that is used as a vacuum reservoir 701 tomonitor the pressure or vacuum between the o-rings 323. A vacuum pump703 and vacuum gauge 705 are connected to the vacuum reservoir 701. Whenthe process chamber 301 is under vacuum or elevated to a level aboveatmospheric pressure, a vacuum level in the vacuum reservoir 701 ismonitored. If there is a leak in the o-ring 323 seal, the pressure riseswithin the vacuum reservoir 701 and is then monitored by the vacuumgauge 705. The level of the vacuum gauge 705 is monitored such that ifthere is a leak in the seal, an interlock signal, preferably a digitalsignal, is sent to a controller, which then reacts to maintain a safecondition within the vacuum thermal annealing system 300.

[0049]FIG. 8 is a diagram illustrating details of the exemplary pumpingsystem 230 and the exemplary gas distribution system 235 coupled to theprocess chamber 210 (FIG. 2). The exemplary pumping system 230 includesa roughing pump 801, a turbomolecular pump 803, pump valves 805, avacuum filter 807 and vacuum gauges 809. The roughing pump 801 is usedas a backing pump for the turbomolecular pump 803, and can evacuate theprocess chamber 210 to pressures of approximately 3 torr. Theturbomolecular pump 803 is a drag type pump, which is backed by theroughing pump 801, and can evacuate process chamber 210 to pressureslower than 10⁻⁵ torr, depending on conditions such as pumping time,temperature, moisture, and out-gassing of different materials in theprocess chamber 210. The pump valves 805 are standard valves used toisolate selected parts of the pumping line, and can be drivenelectrically, pneumatically, or manually. Furthermore, the pump-valves805 can also be used for soft rough pumping and soft venting techniqueswhich reduce the number of particles in the process chamber 210. Bothsoft roughing and soft venting can be accomplished by slowly opening avalve as a function of chamber pressure so that pumping is done slowlyand uniformly. The vacuum filter 807, which can be as simple as a wiremesh or as complex as a chemically reactive filter, is used to keep theprocess chamber 210 free of particulates and contaminants originating inthe pumping system 230, and to keep the turbomolecular pump 803 and theroughing pump 801 clean.

[0050] The exemplary gas distribution system 235 may only include a gaspressure regulator, or may include a mass flow assembly 811 having massflow controllers 813, flow valves 815, a mixing manifold 817, a gasheater 819, a gas pressure and flow regulating system 821, and a gasdistribution manifold 823. The gas distribution manifold 823 may beexternally heated to maintain the temperature of the heated gas withinthe manifold.

[0051] Each mass flow controller 813 controls and regulates an amount ofmass of a gas that is allowed to pass through the mass flow controller813 to the process chamber 210. Typically, the mass flow controller 813measures the mass of gas flowing through the mass flow controller 813using well established techniques such as heat capacity measurements.Consequently, the mass flow controller 813 controls the gas flow withthe use of an internal valve (not shown) located within the mass flowcontroller 813. Gas flow is increased and decreased by respectivelyopening and closing the internal valve located within the mass flowcontroller 813. By attaching several mass flow controllers 813 inparallel as shown in FIG. 8, different gases can be mixed very precisely(in the mixing manifold 817) since the flow of each gas can be preciselycontrolled.

[0052] Further, substrates can be doped with different elements ofcompounds by mixing a correct ratio of gases, and injecting the gasmixture into the processing chamber 210. The doping rate and uniformitycan further be controlled by adjusting a temperature of the substrate.Since the vacuum thermal annealing furnace 200 can precisely control twoprocessing parameters, gas ratio and temperature, the vacuum thermalannealing furnace 200 (FIG. 2) is suitable for doping wafers as well asannealing substrates.

[0053] Substrates are annealed by gases from the gas heater 819.Initially, the gas pressure and flow regulating system 821, whichincludes conventional valves and pressure regulators, controls theamount of gas which flows into the gas heater 819. The heated gas flowsto the gas distribution manifold 823 comprised of a tube with smallholes, designed to deliver the gas uniformly across all of thesubstrates in the process chamber 210. In a one embodiment, specialinjectors may be used to inject the heated gas planar to the surface ofthe substrates. In order to achieve uniform gas flow across thesubstrates, the holes can be made of different sizes to compensate forpressure drops across the tube. The uniform gas flow across thesubstrate results in uniform substrate heating. It should be noted thatthe gas heater 819 and chamber wall heater 825 are typically electricalresistive heaters, but may be inductive heaters or some other type ofheater known to one skilled in the art, which are further discussed withreference to FIG. 9.

[0054]FIG. 9 is a diagram illustrating details of the exemplary gasheater 819 of FIG. 8. Typically, the gas heater 819 is electricallyresistive, and includes a heater housing 901, a resistive heatingelement 903, an electrical insulation mechanism 905, a gas pipe 907, acontroller/power supply 909, and a thermocouple 911. Typically, theheater housing 901 is a stainless steel cylindrical canister, but can bemade of alternative materials, and can be of any shape necessary.

[0055] The gas heater 819 is usually constructed by wrapping a gas pipe907 around the resistive heating element 903, typically a Tungsten rod.Alternatively, the resistive heating element 903 can be any material ofsufficient electrical resistance to generate appropriate heat whencurrent is passed through the resistive heating element 903. The gaspipe 907 is usually a thin wall metal tube such as electro-polishedstainless steel tubing, but may also be made out of any conventionalpiping material which is suitable for this application. The gas pipingmay also be made from the same ceramic material as the chamber liner 303(FIG. 3) such as zirconia. Heat output from the resistive heatingelement 903 is controlled by an amount of current sent through theresistive heating element 903. The gas pipe 907 is electrically isolatedby the electrical insulation mechanism 905, typically made of mica.Further, the gas pipe 907 is thermally coupled to the heating element903 so that the gas heater 819 can operate efficiently. This thermalcoupling is usually achieved by a sturdy mechanical connection betweenthe gas pipe 907 and the heating element 903.

[0056] The temperature of the gas exiting the gas heater 819 is measuredby the thermocouple 911. The thermocouple 911 is a standard thermocouplewhich is chosen according to a specific application (for example, Kthermocouples are the most popular and have the widest temperaturerange, J thermocouples offer ruggedness and reliability, and Tthermocouples have the narrowest range but are ideal for very precisetemperature measurements under 200° F.). The thermocouple 911 istypically positioned in a gas line after the gas heater 819. However,the position of the thermocouple 911 can be anywhere in the processchamber 210 (FIG. 2), and is chosen so that the best temperature controlof the substrates is achieved for a specific application or process.

[0057] The temperature of the gas is controlled by a feedback loopinvolving the thermocouple 911, the controller/power supply 909, and theresistive heating element 903. The thermocouple 911 measures thetemperature of the gas and outputs temperature data to thecontroller/power supply 909 which may be a standard temperaturecontroller coupled to a standard power supply. The power supply may bevoltage or current regulated. The controller/power supply 909 uses thesetemperature data to calculate the amount of power needed to reach and/ormaintain a predetermined temperature set-point. Further, thecontroller/power supply 909 delivers appropriate power for temperaturecontrol by adjusting output voltage and/or current to the resistiveheating element 903. Control/power supply 909 typically uses a PID(proportional-integral-derivative) algorithm to calculate and adjust anoutput power. Alternatively, other types of system control algorithmsmay be utilized. The temperature control algorithm is further discussedin conjunction with FIGS. 11A and 11B below.

[0058] The gas heater 819 usually uses inert gases, such as Argon, as aheating gas but other reactive gases may be used. Inert gases arepreferred because reactive gases, when heated, may react with the gaspipe 907 causing damage to the system. However, if a process requiresheated reactive gases to be injected into the process chamber 210, thepresent embodiment is equipped to handle reactive gases. The primaryfunction of the gas heater 819 is to assist in achieving goodtemperature uniformity across a substrate during the annealing or otherprocess, and to rapidly heat the process chamber 210 and substrate tothe temperature set-point.

[0059] Simultaneously with the flow of heated gas, the chamber wallheater 825 (FIG. 8) temperature is reduced. The chamber wall heater 825,as is further discussed below, is typically used to maintain thetemperature of the substrates and process chamber 210 or 301 at a hightemperature set-point but can also be used to do the majority of theheating, if desired. Like the gas heater 819, the chamber wall heater825 may be an electrical resistive heater which heats up the processchamber 210 by sending current though electrically resistive elements.The chamber wall heater 825 is thermally coupled to the chamber wall,usually by a direct mechanical connection. A heat output from thechamber wall heater 825 is controlled by adjusting power based on datafrom the thermocouple 911. The chamber wall heater 825 also uses acontrol scheme such as a PID algorithm to control its power output. Oncethe chamber wall heater 825 is thermally stable, the heated gas flow isreduced and heat from the chamber wall heater 825 maintains a constanttemperature for an appropriate amount of time.

[0060]FIG. 10 is a flowchart illustrating an exemplary method forloading and processing one or more substrates in the vacuum thermalannealing furnace 200 (FIG. 2). In step 1001, the substrates are loadedinto the vacuum thermal annealing furnace 200, and a process recipe isselected. The substrates can be loaded by positioning the substrates intheir cassettes so that the optional robot 225 (FIG. 2) can load thesubstrates into the substrate holder 215 (FIG. 2). Alternatively, thesubstrates can be manually loaded onto the pedestals 607, 603 (FIG. 6)of the substrate holder 215. The process recipe usually includes atemperature ramp-up rate, a temperature set-point, a dwell time, atemperature ramp-down rate, and a selection of which mass flowcontrollers 813 (FIG. 8) is used. The process recipe is selected from aplurality of recipes on the control system 240. Alternatively, a usermay enter a custom recipe into the control system 240. Next in step1003, the substrates are transferred into the substrates holder 215 bythe optional robot (if used). Step 1003 is skipped if the substrates aremanually loaded into the substrate holder 215 in step 1001.

[0061] Once the substrate holder 215 has been moved into the processchamber 210 in step 1005 and the set of o-rings 323 forms a seal, avacuum is created in the process chamber 210 in step 1007. The vacuumdrawn on the process chamber 210 removes both air and outgassed residualmaterials. Pressure in the process chamber 210 is monitored by thevacuum gauges 809 (FIG. 8). In step 1009, a decision is made as towhether the process chamber 210 has reached a sufficient vacuum level.If the desired vacuum level has been reached, then heated gas isinjected into the process chamber 210 planar to the substrate. If thevacuum thermal annealing furnace 200 is only used to anneal substrates,heated gas is allowed to flow into the process chamber 210 through thegas heater 819 (FIG. 8). Alternatively, if the vacuum thermal annealingfurnace 200 is used to dope substrates 819 then gas is allowed to flowthrough the mass flow assembly 811 (FIG. 8) and mixing manifold 817(FIG. 8). During this gas flow process, pressure in the process chamber210 is quickly raised by closing the vacuum valve 815 (FIG. 8). Thepressure in the process chamber 210 is maintained by the programmableexhaust valve 325 (FIG. 3), which is controlled by the software of thecontrol system 240 (FIG. 2). A typical processing pressure for theannealing process is 69 kPa (approximately 10 psia). A regulatingtransducer (not shown) is used through which the heated gas exhausts andmaintains the chamber pressure, thus allowing the heated gas to remainat the surface of the substrate (residence time) to transfer energy fromthe gas to the substrate. There is a constant supply of heated gas,which replaces the energy that is transferred to the substrate.Furthermore, the chamber wall heater 825 (FIG. 8) will turn on to helpmaintain an appropriate temperature. Thus, the heated gas quicklyapplies thermal energy uniformly across the substrate, while the chamberwall heater 825 is used to maintain a constant temperature for thelength of the annealing cycle, which may be as long as one hour or more.

[0062] The resistive heater coil (not shown) may be replace by aninductive heater that includes a magnetic resonator that is used toproduce the thermal energy. The basic premise of the annealing cycleremains the same for any type of chamber wall heater 825.

[0063] As the process gas is allowed into the process chamber 210, thesubstrates are heated to a temperature set-point and allowed to remainat this temperature for a set time in step 1011. The temperature controlalgorithm is further discussed with reference to FIGS. 11A and 11Bbelow. Once the set-time has elapsed, the substrates are cooled byramping down the temperature at a controlled predetermined rate in step1013. The cooling process can be accomplished by flowing cool gas overthe chamber wall heater 825, and can be accelerated by equipping thechamber walls with water cooling tubes (not shown) having cold watercirculating therein. A controlled cooling is achieved by opening andclosing flow valves 815 (FIG. 8) in the mass flow assembly 811 and thegas pressure and flow regulating system 821 (FIG. 8). If rapid coolingis desired, then the flow valve 815 in the mass flow assembly 811 isopened, and the flow valve 815 in gas pressure and flow regulatingsystem 821 is closed allowing only cold gas to flow over the chamberwall heater 825. The chamber wall heater 825 and the substrates in theprocessing chamber 210 are then both cool rapidly. As the substrates arecooled, the temperature of the chamber wall heater 825 is monitored bythe thermocouple(s) 911 (FIG. 9).

[0064] In step 1015, a decision is made as to whether the processchamber 210 is cool enough to be opened safely. If a safe temperaturehas been reached (typically 50° C.), the process chamber 210 is ventedin step 1017. The pressure in process chamber 210 is monitored duringthe venting in step 1017, and when a decision is made in step 1019 thatambient pressure has been reached, the substrates are unloaded in step1021. The unloading process consists of transferring the substrateholder 215 out of the process chamber 210 with either the optional robot225 or manually.

[0065]FIG. 11 is a flowchart illustrating an exemplary method fortemperature control of the heating cycle of step 1011 of FIG. 11. Instep 1101, the controller/power supply 909 (FIG. 9) receives and storesin memory the process temperature set-point and process dwell time.Next, in step 1103, the temperature of the process chamber 210 (FIG. 2)is measured using the thermocouple 911 (FIG. 9). These measuredtemperature data are transferred to the controller/power supply 909 instep 1105. Subsequently, the measured temperature is compared with theset-point temperature in step 1107.

[0066] Next, in step 1109, a decision is made as to whether thetemperature set-point has been reached. Usually, this decision is madeby comparing the measured temperature value with a tolerance range oftemperatures centered on the temperature set-point. For example, if thetemperature set-point is set at 320° C., the temperature will beconsidered reached if the measured temperature falls between 319.5° C.and 320.5° C. Once the temperature set-point has been reached, anothercheck is preformed in step 1111 to determine if a timer has beenstarted. If the timer has not been started in step 1111 then the timeris started in step 1113. Alternatively, if the timer has been startedthen the timer is allowed to continue running in step 1115. If thetemperature set-point had not been reached in step 1109 then, in step1117, another check is performed to determine if the timer had beenpreviously started. If it is determined in step 1117 that the timer hadbeen previously started and the temperature had not been reached, thenthe user is notified of a temperature control problem by an alarm instep 1119.

[0067] As the timer continues to keep track of elapsed time, anothercheck is performed in step 1121 to determine if the timer has beenrunning for longer than the dwell time. If it is determined in step 1121that the timer time has exceeded the dwell time, then theheating/dwelling cycle is completed, and the process is completed instep 1011 (FIG. 10). Otherwise, in step 1123, the controller/powersupply 909 calculates an amount of power output to send to the heatersto achieve or maintain the set-point temperature. This power outputcalculation is typically performed by a PID algorithm that uses themeasured temperature data and the set-point data to calculate the amountof power required so that the desired temperature set-point is reachedquickly, and is stable during the entire process. Once the power outputis calculated, the controller/power supply 909 sends the correct powerto the heaters in step 1125. This process is then repeatedly continueduntil the time on the timer has exceeded the dwell time in step 1121, oruntil an alarm is sounded, as in step 1119.

[0068]FIG. 11B is a flowchart illustrating an alternative method fortemperature control of the heating cycle of step 1011 of FIG. 10. Inthis alternative embodiment the set-point temperature can be maintainedby keeping the power output of the gas heater 819 (FIG. 8) fixed andadjusting the final temperature of the gas flowing into process chamber210 by controlling a mixture of cold gas and heated gas. Cold gas refersto gas that is at a lower temperature than the heated gas. Cold gasflows through mass flow assembly 811 (FIG. 8), which contains the flowvalves 815 (FIG. 8), whereas heated gas flows through gas heater 819 andgas pressure flow regulating system 821 (FIG. 8) that also contains theflow valves 815. Opening and closing the flow valves 815 mix the hot andcold gases. For example, closing the appropriate flow valves 815 in themass flow assembly 811 and opening the appropriate flow valves 815 inthe gas pressure and flow regulating system 821 increases thetemperature, whereas opening the appropriate flow valves 815 in the massflow assembly 811 and closing the appropriate flow valves in the gaspressure and flow regulating system 821 decreases the temperature.

[0069] In this alternative method, steps 1101 through steps 1121 are thesame as previously discussed with reference to FIG. 11A. In step 1127,the states (opened or closed) of flow valves 815 in the mass flowassembly 811 and the flow valves 815 in the gas pressure and flowregulating system 821 are determined. A similar PID algorithm, as wasdiscussed with reference to step 1123 (FIG. 11A), can be used todetermine when any of the flow valves 815 should be opened or closed andan amount, if any, any of the flow values 815 should be opened. In step1129, signals to open or close each of the flow valves 815 aretransmitted from the controller/power supply 909 (FIG. 9) to the flowvalves 815. For electrical valves, the transmitted signals for openingor closing the flow valves 815 are typically 12 VDC signals or 120 VACsignal. If pneumatic valves are used, then 5 VDC signals are typicallyused to actuate another valve that allows pressurized gas to open orclose the flow valves 815. This alternative embodiment can have asimpler power supply than the previous embodiment of FIG. 11A becausethe power supply can be a set of relays, rather than a voltage orcurrent controlled power supply used in the embodiment of FIG. 11A.

[0070]FIG. 12 is a diagram showing a cut-away side view of analternative embodiment of a vacuum thermal annealing furnace 1201 in aready-to-be-loaded position. The vacuum thermal annealing furnace 1201includes a process chamber 1203, an optional robot 1205, a chamber door1207, a heating element 1209, a rotating substrate holder 1211, arotating shaft and motor assembly 1213, a vacuum pipe and flange 1215, apumping system 1217, and a gas heating system 1219.

[0071] The process chamber 1203 is a vacuum chamber typically made ofstainless steel or aluminum that can hold one substrate but which can becoupled together with other identical process chambers 1203 creating onetool capable of processing multiple substrates as further described withreference to FIG. 13. The inside of the process chamber 1203 can also belined with a liner, usually made out of a metal or ceramic such aszirconium. The purpose of the liner is to make the process chamber 1203easier to maintain as well as improve the heating characteristics of theprocess chamber 1203. The optional robot 1205 is a standard robot, asdescribed earlier in FIG. 2, and is used to transfer substrates betweenthe process chamber 1203 and, for example, a substrate cassette holder(not shown). Heating element 1209 is typically a resistive heatingelement made out of a high resistance material such as Tungsten and isheated by running current through it. The rotating substrate holder 1211supports the substrates during processing and is coupled to the rotatingshaft and motor assembly 1213. Additionally, the rotating substrateholder 4211 is constructed from materials with favorable heat transferproperties, such as aluminum or zirconium. The rotating shaft and motorassembly 1213 is typically an electrically or pneumatically poweredmotor that drives a shaft (usually metallic) mounted to a motor.

[0072] This alternative embodiment of vacuum thermal annealing furnace1201 begins the annealing process by loading a substrate into theprocess chamber 1203, either manually or with the optional robot 1205.After the single substrate is loaded onto the rotating substrate holder1211, the chamber door 1207 is closed forming a vacuum type processingchamber. The chamber door 1207, typically made of stainless steel oraluminum, is hinged to a wall of the process chamber 1203, and has ano-ring grove that supports an o-ring. A vacuum seal is created when thechamber door 1207 is closed and the o-ring makes contact with anexterior portion of a wall of the process chamber 1203. The pumpingsystem 1217 then evacuates the process chamber 1203 by pumping gasthrough the vacuum pipe and flange 1215. Subsequently, the rotatingshaft and motor assembly 1213 rotates the rotating substrate holder 1211as the heating element 1209 heats the substrate. The gas heating system1219 assists in the heating process by preheating the gas within the gasheating system 1219, and injecting that preheated gas into the processchamber 1203 as previously described in more detail in the embodiment ofFIG. 8.

[0073] The substrate heating system of this alternative embodiment isslightly different than the substrate heating system used in the firstembodiment described in FIG. 8. The alternative heating system includesthe heating element 1209, which is typically a resistance heatingelement wound in, for example, a spiral shape coil located directlyabove the substrate. The heating element 1209 heats the substrate byboth radiating heat down on to the substrate and also through heatconvention and conduction, if enough exchange gas is present. Heatinguniformity across a substrate in an angular direction is achieved byrotating the substrate with the rotating shaft and motor assembly 1213.Radial heating uniformity across the substrate is further achieved bythe spiral design of the resistive heating element 1209. However, itshould be noted that other designs for the heating element 1209 may beused to achieve uniform heating across a substrate. This alternativeheating system uses the same temperature control algorithm and method ofsupplying power to the heater as that of the first embodiment discussedwith reference to FIGS. 10, 11A, and 11B. The pumping system 1217 andmethod are also the same as that discussed in the first embodiment.

[0074]FIG. 13 is a diagram showing several vacuum thermal annealingfurnaces 1201 (FIG. 12) coupled together to form a single vacuum thermalannealing system 1301 having several processing chambers 1203, a singlepumping system 1217, a single gas heating system 1219, and a singleoptional robot 1205. The components of FIG. 13 were all discussed indetail with reference to FIG. 12.

[0075] The single substrate vacuum thermal annealing furnace 1201discussed with reference to FIG. 12 can be coupled together by stackingthem on top of each as shown in FIG. 13. The advantages of such a designare that all of the individual vacuum thermal annealing furnaces 1201are supported by the single optional robot 1205, the single pumpingstation 1217, and the single gas heating system 1219, making the vacuumthermal annealing system 1301 very cost effective. Additionally, thevacuum thermal annealing system 1301 allows for easy scalability byeither adding or removing processing chambers 1203 depending on theneeds of a business. This vacuum thermal annealing system 1301 alsoaffords the versatility of running different processes in differentprocess chambers 1203 concurrently because each process chamber 1203 issufficiently isolated from the other process chambers 1203. Substratescan also undergo consecutive processes by running one process in a firstprocess chamber, transferring the substrates to a second process chamber1203, and running another process. Consecutive processing isadvantageous in situations where annealing and doping are preferablydone in separate chambers due to problems such as cross-contamination.

[0076] Although this alternative embodiment of the vacuum thermalannealing system 1301 can process a plurality of substrates as does thevacuum thermal annealing furnace 200 (FIG. 2) of the first embodiment,there are advantages and disadvantages to using this alternativeembodiment of FIG. 13. An advantage of this alternative embodiment isthat each substrate can be processed individually in separate processingchambers 1203, whereas in the first embodiment all substrates must beprocessed in one process chamber 1203. Another advantage of thisalternative embodiment is that in the event of a heater malfunction,only one substrate is lost. Conversely multiple substrates could be lostduring a heater malfunction in the first embodiment. The disadvantagesof this alternative embodiment, however, are that this alternativeembodiment is slower and less efficient since the substrates are notprocessed in batches.

[0077] In addition to annealing substrates, the vacuum thermal annealingfurnace 200 (FIG. 2) can also be used to dope semiconductor devices onsubstrates with small amounts of elements or compounds. Doping isaccomplished by introducing a doping element, in gaseous form, to thesubstrate through a gas distribution system such as the system describedin FIG. 8. To dope substrates, the temperature of the vacuum thermalannealer 200 is elevated to as high as 900° C. When used at a hightemperature, water cooling channels may be added to the chamber door 315(FIG. 3) to keep the o-rings 323 (FIG. 3) from degrading.

[0078] Furthermore, the vacuum thermal annealer 200 can be used tooxidize semiconductor devices. This is especially true for oxides thatare very thin, for example, below 400 Angstroms. In this oxidationprocess, typically, ultra-high purity oxygen is flowed within theprocess chamber 301 (FIG. 3) and oxidizes the substrates 605, 601 (FIG.6). Since the vacuum thermal annealer 200 removes air, moisture, andother unwanted materials, a resulting oxide (e.g., silicon dioxide) mayhave a more desirable dielectric integrity for use with advancedmicrocircuits. Additionally, the vacuum thermal annealer 200 can be usedto thermally process materials such as borophosphosilicate glass (BPSG),which require reflow after deposition. In yet a further embodiment, thevacuum thermal annealer 200 can be used to thermally process or curelow-k (i.e., low-permittivity) or ultra low-k dielectric materials.

[0079] The invention has been described above with reference to specificembodiments. It will be apparent to those skilled in the art thatvarious modifications may be made and other embodiments can be usedwithout departing from the broader scope of the invention. Therefore,these and other variations upon the specific embodiments are intended tobe covered by the present invention, and thus are only limited by thescope of the claims when given their broadest, reasonableinterpretation.

What is claimed is:
 1. A vacuum thermal processing system, comprising: aprocessing chamber; a heater coupled to the process chamber; a vacuumflange coupled to the process chamber, the vacuum flange designed to becoupled to a pumping system; at least one substrate holder containedwithin the process chamber configured to hold at least one substrate foreach of the at least one substrate holder; and a gas injector systemcontained within the process chamber, the gas injector system configuredin a way so as to flow gas in an essentially planar fashion to a facesurface of the substrate.
 2. The vacuum thermal processing system ofclaim 1, wherein the process chamber is coupled to a gas distributionsystem.
 3. The vacuum thermal processing system of claim 2, furthercomprising a gas heater system coupled downstream from the gasdistribution system and further coupled upstream of the process chamber.4. The vacuum thermal processing system of claim 1, further comprising ameans of rotating the substrate holder in a direction parallel to theface surface of the substrate.
 5. The vacuum thermal processing systemof claim 1, wherein a plurality of process chambers may be coupledtogether while designed to be coupled to a common gas heating system andfurther designed to be coupled to a common pumping system.
 6. The vacuumthermal processing system of claim 1, wherein the system is used forannealing substrates.
 7. The vacuum thermal processing system of claim1, wherein the system is used for oxidizing substrates.
 8. The vacuumthermal processing system of claim 1, wherein the system is used forimplanting dopants into a semiconductor substrate by injecting a dopantgas into the gas injector system.
 9. The vacuum thermal processingsystem of claim 1, wherein the heater is located in proximity to thesubstrate.
 10. The vacuum thermal processing system of claim 1, whereinthe heater is located in at least one wall of the process chamber. 11.The vacuum thermal processing system of claim 1, wherein a thermalcontrol system is coupled to monitor and maintains a temperature withinthe process chamber.
 12. The vacuum thermal processing system of claim1, wherein the gas injector system contains a plurality of orifices. 13.The vacuum thermal processing system of claim 12, wherein the orificeshave an aspect ratio of between 4:1 and 10:1 as compared with a distancebetween a wall of the gas injector and the substrate, and a diameter ofthe orifice.
 14. A method for annealing a substrate, comprising thesteps of: creating a vacuum in a process chamber; uniformly and rapidlyheating the substrate to a set-point temperature with at least oneheated gas; maintaining the set-point temperature for a desired amountof time; and upon expiration of the desired amount of time, rapidlycooling the substrate.
 15. The method of claim 14, wherein the substrateis rotated essentially parallel to a face of the substrate while the atleast one heated gas is flowing.
 16. The method of claim 14, wherein thesubstrate is rotated essentially parallel to a face of the substratewhile the substrate is within the process chamber.
 17. The method ofclaim 14 wherein the heated gas is super-heated.
 18. The method of claim14 wherein the step of cooling is accomplished using a super-cooled gas.19. The method of claim 14, wherein a pressure within the processchamber is raised to approximately 69 kPa after the step of uniformlyand rapidly heating the substrate has occurred.
 20. A method foroxidizing a substrate, comprising the steps of: creating a vacuum in aprocess chamber; uniformly and rapidly heating the substrate to aset-point temperature with heated oxygen gas; maintaining the set-pointtemperature for a desired amount of time; and upon expiration of thedesired amount of time, rapidly cooling the substrate.
 21. The method ofclaim 20, wherein the substrate is rotated essentially parallel to aface of the substrate while the heated oxygen gas is flowing.
 22. Themethod of claim 20, wherein the substrate is rotated essentiallyparallel to a face of the substrate while the substrate is within theprocess chamber.
 23. The method of claim 20 wherein the heated gas issuper-heated.
 24. The method of claim 20 wherein the step of cooling isaccomplished using a super-cooled gas.
 25. A method for implantingdopants into a semiconductor substrate, comprising the steps of:creating a vacuum in a process chamber; uniformly and rapidly heatingthe semiconductor substrate to a set-point temperature with at least oneheated dopant gas; maintaining the set-point temperature for a desiredamount of time; and upon expiration of the desired amount of time,rapidly cooling the substrate.
 26. The method of claim 25, wherein thesubstrate is rotated essentially parallel to a face of the substratewhile the at least one heated dopant gas is flowing.
 27. The method ofclaim 25, wherein the set-point temperature is approximately 900° C. 28.The method of claim 25, wherein the set-point temperature may be set tobe anywhere within a range from approximately 100° C. to 400° C.
 29. Avacuum thermal processing system, comprising: a processing chamber; aheater coupled to the process chamber; a gas distribution system coupledto the process chamber; a gas heater system coupled between the gasdistribution system and the process chamber; a programmable exhaustvalve for maintaining a pressure within the process chamber; a vacuumflange coupled to the process chamber, the vacuum flange designed to becoupled to a pumping system for creating a vacuum within the processchamber; at least one rotatable substrate holder contained within theprocess chamber configured to hold at least one substrate for each ofthe at least one substrate holder; and a gas injector system containedwithin the process chamber, the gas injector system configured in a wayso as to flow super-heated and super-cooled gas in an essentially planarfashion to a face surface of the substrate.
 30. A system for annealing asubstrate, comprising: means for creating a vacuum in a process chamber;means for uniformly and rapidly heating the substrate to a set-pointtemperature with at least one heated gas; means for maintaining theset-point temperature for a desired amount of time; and upon expirationof the desired amount of time, means for rapidly cooling the substrate.